The invention relates to a method and a device for opening and cleaning fiber material according to the claims.
Such a method is needed to effectively clean fiber material, in particular cotton fibers, as early as possible, i.e. after a bale opening process. Automatic high performance picking and ginning methods used in cotton picking and ginning have caused a large increase in the degree of soiling of many kinds of cotton.
With the performance requirements constantly rising, the cleaning machines have to process these cotton fibers, while trying to maintain the quality of the fiber stock and treat the same most carefully. This is true all the more since the number of opening and cleaning stages in the opening room should be reduced to a minimum, as desired in practice.
In a known device for opening and cleaning fiber material (German Laid Open 10 73 915), the fiber flocks supplied are intensively cleaned by being accelerated several times during their passage through the device, while being simultaneously turned over and guided several times over the respective associated grate segments by two opener rolls. A such horizontal drum opener and cleaner has two parallel drums provided with pins and rotating in the same direction, to which fiber material is fed pneumatically in the axial direction and from which the fiber material is pneumatically taken off axially. It is a drawback of such an opening and cleaning device that the fiber material passes over the grate segments only a few times after entering the device since the fiber material, after having been caught in their axial line of flight by the air flow rotating along with the opening rolls, describes a comparatively steep helical line on the circumference of the opener rolls. As a result, the opening of the fiber material and thus the cleaning thereof is not optimal. A deflecting plate arranged above and between the opener rolls does not allow an intensification of the cleaning since it does not entail a higher number of revolutions of the fiber material around the opener rolls, but rather increases the loss in pressure of the transport air.
In a further known device for opening and cleaning fiber material (German Laid Open 33 33 750), two opener rolls, rotating in the same direction, are adjacently supported in parallel in a horizontal plane above grate segments, the circles of action almost contacting each other in the horizontal plane. Below the axis of rotation, a tapered guide sheet is arranged in the nip of the circles of action.
Similar prior art is also disclosed in the generic Swiss Patent 357307. Also in this opening and cleaning device, there is a separating plate arranged between the rolls as a baffle surface. The feed and suction channel extends transversal to the axes of the opener rolls. The separating plate causes a heavy interference with the air flow and thus causes flow losses that result in an increased consumption of air and power. Further, the implementation does not allow a sufficient separation of the air flow and the fiber material flow.